The goals were scored by Timo Werner (in the second minute), Claudinho (in the 38th minute) and Serdar Azmun (in the 42nd minute).
The game of the sixth round of Group H is being played on the field of the Gazprom Arena stadium in St. Petersburg.
From a tournament point of view, the match in St. Petersburg has no meaning for Zenit: the team from the banks of the Neva has already guaranteed itself a third place and an entry into the Europa League.
Chelsea are fighting Juventus for the first place in Group N.
Earlier it was reported that Liverpool beat Milan and left the Italian club without European cups.